Self-cleaning cutting die with stripper element



F. s. DOMKA 3,283,630 SELF-CLEANING CUTTING DIE WITH STRIPPER ELEMENT Nov. 8, 1966 Filed Oct. 6, 1964 INVENTO/Z. FRANK 5. Dom/( BY dm orv, SETTLE 8. (Sm/e Q'rroR NEVS United States Patent 3,283,630 SELF-CLEANING CUTTING DIE WITH STRIPPER ELEMENT Frank S. Domka, 26814 Kean St., Inkster, Mich. Filed Oct. 6, 1964, Ser. No. 401,880 2 Claims. (Cl. 83-124) This invention relates to cutters for sheet materials and more particularly to self-cleaning cutting dies with stripper elements for cutting holes in various types of sheet stock such as gasket materials, paper stock, cork, plastic and the like, and is an improvement of the cutting die disclosed in my Patent 3,137,188, issued June 16, 1964.

The above referred to patent discloses a commercially successful die which overcomes many of the prior difficulties and the present application is for an improvement, because it provides for a new alignment of operating parts and the adjustability thereof for the purpose of various uses and is arranged to provide a physical compact unit which may be used individually or in combination with other like dies and stored away when not in use and returned to service without any adjustment whatsoever. The die also is arranged to provide for the proper ejector and stripping'arrangement to avoid manual participation.

It is therefore an object of my invention to provide an improved cutting die.

Another object of my invention is to provide an improved cutting die wherein the ejector thereof remains in proper alignment with its housing and its eifectiveness'is controlled to meet varying conditions.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In the drawings:

FIGURE 1 is a view in elevation of the die embodying features of my invention;

FIGURE 2 is a top view of the die shown in FIGURE 1, without the upper parts of the die;

FIGURE 3 is a view in cross section illustrating the device in the position of severing a portion from a sheet of material;

FIGURE 4 is a view in cross section illustrating withdrawal of the die and the cut slug from the stock and the position of parts at the time when the ejector contacts the slug to begin the self-cleaning action;

FIGURE 5 is a view in cross section illustrating the further withdrawal of the die from the stock at the exact moment of completion of the ejection step, and

FIGURE 6 is a side view of a modified form of stripper.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

In accordance with my invention, I provide an improved self-cleaning cutting die with a stripper element. The die includes a tubular element having a cutting edge on one end and an adjustable cap on the opposite end. An ejector is slidably positioned in the tubular member and guided in its movement's therein by a pin movable in diametrically opposed slots in said tubular element. The action of said ejector is controlled by a spring positioned between the adjustable cap and the ejector. By this diametrically opposed slots and pin arrangement, the ejector stays in correct alignment within its housing in the tubular element, and the effectiveness of the ejector may be varied by movement of the adjustable cap to thereby suit various working conditions on different materials or due to wear of the cutting edge of the tubular element. This adjustable cap locks in the spring in the tubular element so as to provide a compact unit which may be stored away when not in use and returned to service as a unit. This type of die may be used individually or in combination with other like dies.

Referring'to the drawings, the numeral 5 designates in general my improved die. The die includes a tubular body element or cutter 10 having an exterior bevel 12 formed on its lower end that tapers to a cutting edge 14. The element 10 is provided with diametrically opposed elongated axially extending slots 16 having semi-circular ends 18 and 20. The slots terminate above the cutting edge 14 and below the top of the element 10. The end of the element 10 opposite the cutting edge 14 is closed by an adjustable screw threaded cap 23.

An ejector 24, which is of cylindrical formation, but

may be of various shapes, is positioned within the interior bore 26 of the tubular cutter 10 and has an outside diametrically opposed apertures 34 and 36. The ejector 24 is provided with a bore 40 adjacent the top end thereof and it extends diametrically therethrough. A pin 38 is passed through aperture 34, bore 40 and aperture 36. The pin 38 may be solid or hollow like a tube. In the present instance, the pin 38 is hollow as shown at 39 thereby permitting any suitable tool (not shown) having a circular body and a tapered end to be inserted in the hollow ends of the pin to expand the pin ends to lock the pin in the apertures 34 and 36 of the stripper 28. If desired, the pin 38 may be press-fitted in apertures 34 and 36. This pin arrangement provides a connection between the ejector 24 and stripper 28 whereby these units move together in a unitary manner.

As will be noted in FIGURES 3, 4 and 5, thebottom end '42 of the ejector 24 forms an ejector or slug engaging portion that is spaced approximately the thickness of the stock to be cut away from the lower edge 45 of stripper 28. As will be described later, this spaces the ejector above the stock during cutting and provides the novel self-cleaning cutting action and ejection function provided by the present invention.

Within the bore 26 of cutter 10 is positioned a spring 43 between the ejector 24 and the adjustable cap 23. By adjusting the cap 23, the effectiveness of the spring 43 is varied. The spring 43 is for the purpose of pushing the ejector 24 and the stripper downwardly to provide the self-cleaning and delayed ejection function of the present invention. In view of cap 23, the spring 43 is locked in position, and there is provided a compact and completely assembled die unit which may be stored away when not in use.

The die unit 5 is suitably mounted for operation on a platen 44 of a suitable cutting press, the platen 44 being provided with a hole 46 to receive the exterior surface of the tubular cutter 10 as a press-fit. The upper part of the cutter 10 may be serrated if desired. After the cutter 10 is fitted in hole 46, a back-up plate 50 is fastened to the platen 44 above the cutter 10 and cap 23 by means of screws 52.

As shown in FIGURE 3, the platen 44 has been brought downwardly in the arrow 54 direction until the cutting edge 14 has penetrated completely through the thickness 7 of the sheet stock material 56. As previously mentioned, the bottom end 42 of ejector 24 is spaced rearwardly of the lower edge 45 of stripper 28.

Thus, as the cutting edge 14 moves downwardly through the stock, the edge 45 contacts the top of the stock and forces the pin 38 and the ejector 24 upwardly so that the bottom edge 42 is retained in noncontacting relation above the top surface of the stock at the time the cut is made.

As shown in FIGURE 4, the tubular cutter 10 has been retracted from the stock to a point where the cutting edge 14 is just above the top surface of the stock. It will be noted that the spring 43 has forced the ejector 24 downwardly relative to the tubular cutter 10, maintaining the edge 45 on top of the stock and the bottom surface 42 of the ejector 24 is now in contacting relationship with the top of the slug 58 that has been removed from the sheet stock 56 because of its friction or press fit within the interior bore 26 of the tubular cutter 10. At this point, the slug has been lifted free of the stock and the self-cleaning action and delayed ejection is about to take place.

As shown in FIGURE 5, the tubular cutter has been removed still farther away from the upper surface of stock 56 and the slug 58 has just been completely ejected past the cutting edge 14 to fall free as the cutter 10 will continue to move away from the stock in the arrow 60 direction. It will be noted that the spring 43 has continued to expand and force the cylindrical ejector 24 downwardly in the arrow 54 direction maintaining the edge 45 in contact with the upper surface of the stock 56 until the pin 38 has now reached the bottom end 20 of the elongated slot 16. At this point, the slug 58 is beginning to drop away as the cutter 10 continues its movement away from the stock in the arrow 60 direction, so that the slug will be dropped gently and loosely on top of the stock.

Therefore, as shown in FIGURE 5, when the cutter 10 is being retracted and the lug 58 is just at its fully ejected position, it will fall vertically downwardly out of the machine adjacent and along the top surface of the stock 56 and the stock will be automatically cleaned as will the die.

In FIGURE 6 I have shown a modified form of stripper designated 128. This stripper 128 is tubular the same as stripper 28 except that it has a portion cut away as at 130 to provide a partial stripping ring on its lower surface 132 while the stripper 28 has a full ring on its lower surface. Stripper 128 is used in die in the same manner as stripper 28 is used. In some instances with certain material the partial or about one-half ring insures ejection of the cut slugs.

From the foregoing it will be readily apparent that I have provided an improved cutting die in which the ejector is maintained in proper alignment in its housing the cutter 10 and this is accomplished by the pin 38 extending through diametrically opposed slots. Furthermore, the die is assembled as a unitary structure with provisions for varying the effectiveness of the ejector arrangement.

I claim:

1. In a substantially horizontally disposed self-cleaning cutting die, a platen, a tubular body having a wall and a cutting edge at one end thereof secured to the platen, diametrically opposed elongated slots in said wall and extending lengthwise of said body and terminating in spaced relation from said cutting edge, an ejector positioned in slidable relation within said tubular body and having a passage extending therethrough in alignment with said slots, a stripper positioned in slidable relation over the outside of said tubular body and having diametrically opposed apertures in alignment with said passage and slots, a pin extending through said apertures, passage and slots, and spring means interposed between the ejector and the platen to induce relative movement between the cutting edge of the tubular body and the ejector after the cutting edge has been moved to clear the upper surface of the material being cut, said stripper having a partial ring on its stripper outer surface.

2. In a substantially horizontally disposed self-cleaning cutting die, a platen, a tubular body having a wall and a cutting edge at one end thereof secured to the platen, an ejector positioned in slidable relation within said tubular body, a stripper positioned in slidable relation over the outside of said tubular body and having a partial ring on its outer surface, means connecting said ejector with said stripper in slidable relation with said tubular body, an adjustable cap for said tubular body at the opposite end of said cutting edge, and spring means interposed between said adjustable cap and said ejector to provide for variations of spring function in the relative movement between the cutting edge of the tubular body and the ejector.

References Cited by the Examiner UNITED STATES PATENTS 46,681 3/1865 Lewis 83124 842,603 1/ 1907 Zidovec 83l25 1,847,273 3/1932 Stacey 83l40 X 2,191,836 2/1940 Stromberg et a1. 83-440 X 2,740,475 4/ 1956 Taylor 83136 2,995,058 8/1961 Reiner 83128 X 3,112,666 12/1963 Tauser 83-140 X 3,137,188 6/1964 Domka 83-124 FOREIGN PATENTS 29,531 8/ 1907 Austria.

WILLIAM W. DYER, JR., Primary Examiner.

F. T. YOST, L. B. TAYLOR, Assistant Examiners. 

1. IN A SUBSTANTIALLY HORIZONTALLY DISPOSED SELF-CLEANING CUTTING DIE, A PLATEN, A TUBULAR BODY HAVING A WALL AND A CUTTING EDGE AT ONE END THEREOF SECURED TO THE PLATEN, DIAMETRICALLY OPPOSED ELONGATED SLOTS IN SAID WALL AND EXTENDING LENGTHWISE OF SAID BODY AND TERMINATING IN SPACED RELATION FROM SAID CUTTING EDGE, AN EJECTOR POSITIONED IN SLIDABLE RELATION WITHIN SAID TUBULAR BODY AND HAVING A PASSAGE EXTENDING THERETHROUGH IN ALIGNMENT WITH SAID SLOTS, A STRIPPER POSITIONED IN SLIDABLE RELATION OVER THE OUTSIDE OF SAID TUBULAR BODY AND HVING DIAMETRICALLY OPPOSED APERTURES IN ALIGNMENT WITH SAID PASSAGE AND SLOTS, A PIN EXTENDING THROUGH SAID APERTURES, PASSAGE AND SLOTS, AND SPRING MEANS INTERPOSED BETWEEN THE EJECTOR AND THE PLATEN TO INDUCE RELATIVE MOVEMENT BETWEEN THE CUTTING EDGE OF THE TUBULAR BODY AND THE EJECTOR AFTER THE CUTTING EDGE HAS BEEN MOVED TO CLEAR THE UPPER SURFACE OF THE MATERIAL BEING CUT, SAID STRIPPER HAVING A PARTIAL RING ON ITS STRIPPER OUTER SURFACE. 